Knowing Your Ice Machine’s Production
In many cases we are faced with a service call in which the client believes the ice machine is not making enough ice. It is difficult for the client and sometimes even the technician to determine if there is an underlying problem, especially when the unit is making ice consistently. So how do you know if it’s production is up to par. There is only one way and that is to determine the ice machine’s production.
Most manufacturers will provide equipment specifications such as size, refrigerant charge, voltages, etc. In that documentation you will need to locate the equipment’s ice production capacity. Not all ice machines are create equal, so you will need to narrow it down to your model number. Let us look at an example. We will say you have a Scotsman Prodigy C0530 – air-cooled ice machine. First find the manufacturers capacity in the specification documents. Most manufacturers will have this information on-line. To the left is an example of what you would find. Next you will need to determine the water temperature being supplied to the unit and the ambient temperature where the unit is located. The ambient temperature is the space temperature.
Now that we have the basic data we need we will move on to the next step. Please note: Tools that you will need to get the most accurate data will be a timer, a scale, and a clean trash bag. The machine will have two parts or cycles. The first is the refrigeration cycle, which makes the ice, and the second is the harvest cycle, which is the dropping of the ice into your storage bin. Once you hear the machine entering the harvest cycle (you will usually hear a higher than normal pressure sound) get your timer ready to go. After the ice has fallen and harvest is completed, you should hear the unit return to its regular cycle. When this occurs start your timer.
Now that your timer is going place the trash bag inside your ice storage bin. You are going to place it so that it will catch the ice that falls during the harvest cycle. I would recommend creating a crater in the bag so it catches all the ice and water droplets. Once in place all you can do is wait for the unit to finish making ice. Once the unit’s next harvest cycle is complete then stop your timer and record it. Next pull the bag out with the collected ice and weigh. Do not drain any water that fell with the ice, as this is normal. Alright gather your data and we will move on to the calculations.
Here is an example of what you might have so far.
- Water supply temperature: 82*F
- Ambient Temperature: 80*F
- Ice Weight: 4.50 lbs.
- Cycle Time: 15 Minutes
Let’s look at determining our production based on the data we collected. The basic formula is weight x 1440/cycle time. The 1440 is the minutes in 24 hours. With our data above we get the following: 4.50 x 1440 = 6480. Then 6480/15 = 432. We see that the final result is 432 lbs. / 24 hour ice production based on our current data. If you review the ice machines capacity you will see that it’s fairly close and therefore the unit is performing as it should.
The two major factors that will affect your unit’s production is the water and ambient temperature. If these increase, your production will decrease. Let us look at another example. Perhaps we find an ice machine sitting inside a warehouse space. Let’s say the ambient temperature is 100*F and water temperature is 90*F. The ice weight is 4.5 lbs. with a cycle time of 26 minutes. If you run the calculation you will see that the ice production is now 249 lbs. per 24 hour period. This production is well below the factory ice capacity data, but at no fault of its own. It’s simply the space conditions that are the factor.
Now let us look back at our original production check (where the water and ambient temperatures was 82 and 80). This time you had a cycle time of 23 minutes. Running the numbers you find the production is now 320 lbs. / 24 hours. Comparing the data to the chart we find that our production is over 100 lbs short and the cycle time is about 7 minutes higher. What could be causing this to happen? If we analysis what we know, we me find the direction to look for potential problem. For now we will assume that the refrigeration components are functioning like they should. If our ice weight is good at 4.5 lbs. per drop then we know our ice if forming properly, the evaporator making the ice is functioning properly, and the unit had enough water during this cycle. This eliminates the water components so we should be move the intake and discharge of air, our condenser area. The intake and discharge should be clear of any obstructions, such as boxes and product. If there is an air filter, it needs to be clean, replaced, or free of obstructions as well. Perhaps you find an air filter and it is in pretty rough shape. The lack of air intake is going to starve the unit of airflow and therefore increase pressures and temperatures. This problem would be the cause of the production issue. Other factors to watch out for is going to be slow water fill, dirty evaporator plates, and sensor cleanliness. These items will also cause a poor performance despite descent water and ambient conditions. I hope that this information has been helpful. Be sure to have your equipment serviced and cleaned routinely, as well as kept in a conditioned space if possible.
One of our tools used to gather water temperature and ambient temperature is the FieldPiece Multimeter. We also used our refrigerant scale to weigh the ice. To see more details check them out on Amazon by clicking the links above. Lastly, if you are looking for a good ice machine cleaner solution check out Nu-Calgon Ice Machine Cleaner. Be sure to always use nickle safe cleaners and stay away from products that are not food grade.